Some wireless communications systems can be configured to logically group sets of mobile wireless radio subscriber units (SUs) into subgroups, sometimes known as talk groups. A talk group includes multiple SUs that are able to participate in a group or dispatch voice call, where all of the SUs in the talk group receive the same voice information, thereby allowing one member of the talk group (or perhaps a dispatcher at a head end location) to talk to every other member of the talk group at substantially the same time over a single shared downlink connection from a base radio.
Some wireless communication systems also support the transmission of group data (in addition to group voice) to all SUs in the talk group. In operation, all of the SUs in the talk group typically receive group data on a single shared downlink connection from the base radio. Examples of group data that SUs in a talk group might receive on the shared downlink connection from the base radio include text messages, file downloads, SU firmware/software updates, SU configuration parameter settings, access/encryption keys, talk group configuration and/or management parameters, and the like.
Most wireless communications systems that allow SUs in a talk group to receive group data messages typically support only unconfirmed delivery of the group data by the SUs in the talk group. Unconfirmed delivery is when the base radio sends the group data to the SUs in the talk group, but the SUs of the talk group do not inform the base radio as to whether they successfully received the group data transmission or not. The primary reasons why most wireless communications systems support only unconfirmed delivery of group data is because (i) existing methods of sending confirmation messages from each SU to the base radio use a lot of radio frequency (RF) resources in the shared wireless network, (ii) for talk groups with a lot of SUs, existing methods of sending confirmation messages from each SU to the base radio take a lot of time especially over lower speed communication channels, and (iii) it is often unnecessary for individual SUs to send receipt confirmations to the base radio if higher layer protocols handle confirmations and retransmission requests (e.g., Transmission Control Protocol (TCP) between the source application and the receiver, or perhaps even higher application layer protocols).
However, in some situations, it is desirable to have the ability to quickly confirm whether all the SUs in a talk group have received a particular group data transmission. One such application is where a large team of operational and/or technical personnel need to receive the same information (e.g., system alarms, security/access codes, text messages, system status updates) very quickly and accurately to coordinate their activities in a large-scale, mission-critical manufacturing, production, communications, and/or police/military operation. In such applications, existing methods of having each SU in the talk group send a confirmation to the base radio and existing methods of using Layer 4 (e.g., TCP) or higher (e.g., application layer) confirmation and retransmission mechanisms may not provide sufficiently fast delivery confirmations, particularly in talk groups having a very large number of SUs communicating over lower speed transmission channels.
Accordingly, there is a need for an improved, bandwidth efficient and time efficient, group data acknowledgement to confirm successful delivery of group data to all SUs in a talk group.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.